Mothers-to-be may be divulging too much pregnancy information on social media, a survey suggests.

Two in five people believe that pregnant women "overshare" details on websites such as Facebook, according to a poll by Netmums and the Department of Health's Start4Life campaign.

Nine in 10 of those surveyed said they had seen an image online of a friend's scan and 22% said they had viewed a photo of a positive pregnancy test.

More than two thirds of people felt that mothers-to-be were more likely to try to show a 'perfect' pregnancy than a realistic one, according to the survey of 2,000 Netmums members who use Facebook. And 62% said they felt friends were more likely to talk about trivial aspects of their pregnancy rather than important matters such as their health.

As a result, the Start4Life campaign - which is distributing two million free booklets to support pregnant women - is encouraging mothers-to-be to share information about their health both on and offline.

Health Minister Dr Dan Poulter said the leaflets are available to all pregnant women through their GPs and midwives.

"Staying healthy in pregnancy is vital to give babies the best possible start in life," said Dr Poulter, who used to work as a hospital doctor specialising in obstetrics, gynaecology and women's health.

"We want to do everything we can to reach out to pregnant women and help them live the healthiest lifestyles they can. These new materials from Start4Life simplify the information out there and provide clear advice on the importance of a healthy pregnancy. The sheer volume of information available to pregnant women - on Facebook and elsewhere - can make it hard to find the best advice."

Netmums founder Siobhan Freegard added: "The internet is often a source of support and advice for mums and mums-to-be, but the relationship many have with Facebook can be complex. Whilst lots of mums enjoy sharing information and offering advice, new trends and the desire to show the best possible image to the world can mean that many mums feel the site piles on the pressure.

"It's never good to worry too much about what people think, and so instead we encourage mums to make the most out of the support available from other mums online and initiatives such as Start4Life."